linuxolator: fatal trap 12 when compiling libX11

[Scot Hetzel]

On 1/16/07, Divacky Roman <xdivac02 at stud.fit.vutbr.cz> wrote:
> please test this patch:
>
> Index: linux_emul.c
> ===================================================================
> RCS file: /home/ncvs/src/sys/compat/linux/linux_emul.c,v
> retrieving revision 1.12
> diff -u -r1.12 linux_emul.c
> --- linux_emul.c        7 Jan 2007 19:09:20 -0000       1.12
> +++ linux_emul.c        16 Jan 2007 22:11:06 -0000
> @@ -170,7 +170,8 @@
>         EMUL_UNLOCK(&emul_lock);
>
>         EMUL_SHARED_WLOCK(&emul_shared_lock);
> -       LIST_REMOVE(em, threads);
> +       if (!LIST_EMPTY(em->shared->threads)

Wouldn't compile as shown above (complained about '->' when
compiling), changed it to:

             if (!LIST_EMPTY(&em->shared->threads))

but now I'm getting:

Fatal trap 9: general protection fault while in kernel mode
cpuid = 0; apic id = 00
instruction pointer     = 0x8:0xffffffffa2cb3b2c
stack pointer           = 0x10:0xffffffffa3135ad0
frame pointer           = 0x10:0xffffffffa3135b10
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 20225 (bash)
panic: from debugger
cpuid = 0
Uptime: 9m59s
Physical memory: 1008 MB

(kgdb) list *0xffffffffa2cb3b2c
0xffffffffa2cb3b2c is in linux_proc_init
(/usr/src/7x/sys-orig/modules/linux/../../compat/linux/linux_emul.c:138).
133                     }
134             }
135             if (child != 0) {
136                     EMUL_UNLOCK(&emul_lock);
137                     EMUL_SHARED_WLOCK(&emul_shared_lock);
138                     LIST_INSERT_HEAD(&em->shared->threads, em, threads);
139                     EMUL_SHARED_WUNLOCK(&emul_shared_lock);
140
141                     p = pfind(child);
142                     /* we might have a sleeping linux_schedtail */
(kgdb) bt
#0  doadump () at pcpu.h:172
During symbol reading, Incomplete CFI data; unspecified registers at
0xffffffff80445bbc.
#1  0xffffffff804464b9 in boot (howto=0x104) at
../../../kern/kern_shutdown.c:411
#2  0xffffffff80445f47 in panic (fmt=0xffffffff806a82a7 "from
debugger") at ../../../kern/kern_shutdown.c:567
#3  0xffffffff801ac8c7 in db_panic (addr=0x0, have_addr=0x0,
count=0x0, modif=0x0) at ../../../ddb/db_command.c:433
#4  0xffffffff801acd69 in db_command_loop () at ../../../ddb/db_command.c:401
#5  0xffffffff801aec73 in db_trap (type=0xa3135830, code=0x0) at
../../../ddb/db_main.c:222
#6  0xffffffff8046c428 in kdb_trap (type=0x9, code=0x0,
tf=0xffffffffa3135a20) at ../../../kern/subr_kdb.c:502
#7  0xffffffff80654f41 in trap_fatal (frame=0xffffffffa3135a20,
eva=0xffffff002d1d9290)
    at ../../../amd64/amd64/trap.c:691
#8  0xffffffff8065551a in trap (frame=0xffffffffa3135a20) at
../../../amd64/amd64/trap.c:499
#9  0xffffffff8063d39e in calltrap () at ../../../amd64/amd64/exception.S:169
#10 0xffffffffa2cb3b2c in linux_proc_init (td=0xffffff002d1d9290,
child=0x4f5c, flags=0x0)
    at /usr/src/7x/sys-orig/modules/linux/../../compat/linux/linux_emul.c:138
#11 0xffffffffa2cbb810 in linux_fork (td=0xffffff002d1d9290, args=0x0)
    at /usr/src/7x/sys-orig/modules/linux/../../amd64/linux32/linux32_machdep.c:467
#12 0xffffffff8068e0a0 in ia32_syscall (frame=0xffffffffa3135c80) at
../../../amd64/ia32/ia32_syscall.c:187
#13 0xffffffff8063d780 in Xint0x80_syscall () at ia32_exception.S:65
#14 0x0000000028192358 in ?? ()
Previous frame inner to this frame (corrupt stack?)
(kgdb) frame 10
#10 0xffffffffa2cb3b2c in linux_proc_init (td=0xffffff002d1d9290,
child=0x4f5c, flags=0x0)
    at /usr/src/7x/sys-orig/modules/linux/../../compat/linux/linux_emul.c:138
138                     LIST_INSERT_HEAD(&em->shared->threads, em, threads);
(kgdb) p &em->shared->threads
$1 = (struct {...} *) 0xdeadc0dedeadc0e6
(kgdb) p *em
$3 = {
  pid = 0xdeadc0de,
  child_set_tid = 0x0,
  child_clear_tid = 0x0,
  shared = 0xdeadc0dedeadc0de,
  pdeath_signal = 0xdeadc0de,
  threads = {
    le_next = 0xdeadc0dedeadc0de,
    le_prev = 0xdeadc0dedeadc0de
  }
}

Scot
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